The subject matter herein relates generally to sensor assemblies that are used to detect the position of at least one movable component.
Some known devices use an electromagnetic coil to cause movement of another component of the device based on a magnetic field generated by the electromagnetic coil. Examples of such known devices include some vehicle differential systems and transmission clutch systems in vehicle applications. The differential system may be a locking differential or a limited slip differential, such that the electromagnetic coil generates a magnetic field to move a disk or ring, which may be rotating or stationary, axially relative to the coil. The disk may be used in a locking differential to lock two wheels attached to the same axle such that the two wheels rotate at the same velocities. The disk alternatively may be used in a limited slip differential that allows the wheels of the same axle to rotate at different velocities while individually controlling the torque applied to each of the two wheels. It may be desirable to track the axial position of the disk relative to the electromagnetic coil, as such data may be used to determine or verify whether the disk is engaged with a locking gear of the differential system that engages the disk or is disengaged from the locking gear at particular times. The data on the position of the disk may also be useful in determining whether maintenance is suggested or necessary, as wear on the disk, the locking gear, or another component may affect the extent of the movement of the disk and the stopping positions of the disk responsive to the magnetic field.
Sensors are often used to track positions of movable components. The sensors must be compact to fit within a casing of the respective device in order to monitor the movement of the moveable component. Although contactless magnetic sensors are generally reliable, such magnetic sensors function based on a sensor magnetic field and are prone to errors and inaccuracies due to magnetic field interference. For example, the coil magnetic field generated by the electromagnetic coil would interfere with a typical magnetic sensor that is located within the coil magnetic field by producing noise that makes it difficult for the sensor to distinguish detected magnetic flux attributable to the sensor magnetic field from magnetic flux attributable to the coil magnetic field, leading to inaccuracies. Moving the magnetic sensor farther away from the electromagnetic coil to reduce the noise from the coil magnetic field in the detected signal may not be practical due to space constraints.
A need remains for a position sensing system that improves the accuracy of position sensing by reducing the effect of an external magnetic field.